The mutant lysine decarboxylase according to [4] or [5], wherein at least one or more of the following replacement
1,5-Pentamethylenediamine is diamine known to be produced by decarboxylation of lysine, i.e., amino acid, and recently, has been gaining attention as biomass-derived polymer materials and intermediates for agricultural chemicals and pharmaceutical products.
As a method for producing 1,5-pentamethylenediamine, for example, a method described in patent document 1 below is known. In this method, amino acid lysine is allowed to react with Escherichia coli-derived lysine decarboxylase for the production.
Although the document describes that the enzyme amount to be used is not restricted, an appropriate amount of necessary enzyme is, in the case of purified enzyme, 25 mg/L to 70 mg/L, and in the case of catalyst resting bacterial cell, 5 g/L to 15 g/L of enzyme. Furthermore, Examples show that 0.97M of 1,5-pentamethylenediamine is produced from 1M of lysine neutralized with adipic acid by using 50 mg/L of purified enzyme with reaction at 45° C. and for 48 hours. However, generally, production of purified enzyme involves a large amount of costs, and therefore preferably, catalyst resting bacterial cell is used as a catalyst for polymer material production. Also, the document shows that 6.6 g/L of 1,5-pentamethylenediamine is produced from a fermentation liquid containing 10 g/L of lysine using 50 mg/L of purified enzyme and performing reaction at 45° C. for 24 hours.
Furthermore, according to Sabo et al., purified Escherichia coli-derived lysine decarboxylase has a specific activity of, per 1 mg of enzyme, 900 to 1100 μmol/min (for example, non-patent document 1 below).
Furthermore, TAKATSUKA et al. shows, with the specific activity of Selenomonas ruminantium-derived lysine decarboxylase, per 1 kg of enzyme, 0.198 mol of 1,5-pentamethylenediamine is produced for one second (for example, non-patent document 2 below).
This is an activity producing 11.88 μmol of 1,5-pentamethylenediamine per 1 mg of enzyme for one minute, and activity of lysine decarboxylase per enzyme is, relative to the Escherichia coli-derived one, about 1/100.
Furthermore, a method in which improvement in activity by modification of Selenomonas ruminantium-derived lysine decarboxylase gene is known (for example, see non-patent document 3 below).
Non-patent document 3 shows that changes in amino acids at two positions achieve an increase in Kcat at a rate of 1.3 times.